This study aims to improve students' critical thinking skills through the implementation of the Problem Based Learning (PBL) model in Pancasila and Civic Education (PPKn) for Class VIIIE at SMP Negeri 5 Madiun. This study employed a Classroom Action Research (CAR) design based on the Kemmis and McTaggart model, which consists of four stages: planning, action, observation, and reflection. The research subjects were 32 students of Class VIIIE at SMP Negeri 5 Madiun. The study was conducted in two cycles, with data collected through observation, tests, and documentation. The data were analyzed using descriptive quantitative and qualitative methods.The results of the study indicate that the implementation of the Problem Based Learning (PBL) model effectively improved students' critical thinking skills. This improvement was reflected in the increase in the average critical thinking score from 68 in the pre-cycle to 76 in Cycle I and further to 84 in Cycle II. The percentage of students achieving learning mastery also increased from 37.5% in the pre-cycle to 71.9% in Cycle I and reached 87.5% in Cycle II. In addition, students' learning activities showed significant improvement, as demonstrated by their enhanced ability to identify problems, analyze information, express opinions, and develop solutions to the given problems. Based on the findings, it can be concluded that the implementation of the Problem Based Learning (PBL) model is effective in improving students' critical thinking skills in Pancasila and Civic Education (PPKn) for Class VIIIE at SMP Negeri 5 Madiun. The Problem Based Learning (PBL) model can serve as an alternative instructional approach that promotes active, meaningful, and student-centered learning.